ACO professional means an individual who is Medicare-enrolled and bills for items and services furnished to Medicare fee-for-service beneficiaries under a Medicare billing number assigned to the TIN of an ACO participant in accordance with applicable Medicare regulations and who is either of the following:
(1) A physician legally authorized to practice medicine and surgery by the State in which he or she performs such function or action.
(2) A practitioner who is one of the following:
(i) A physician assistant (as defined at § 410.74(a)(2) of this chapter).
(ii) A nurse practitioner (as defined at § 410.75(b) of this chapter).
(iii) A clinical nurse specialist (as defined at § 410.76(b) of this chapter).
42 CFR § 425.20
As used in this part, unless otherwise indicated -